Use of simple remote sensing tools to expedite surveys for rare tiger beetles (Insecta: Coleoptera: Cicindelidae)

Tiger beetles (Insecta: Coleoptera: Cicindelidae) often occupy small patches of suitable habitat in otherwise unsuitable landscapes. Such patches are easily overlooked, which may lead to underestimates of both the number of occurrences and the overall population size. In this study, simple World Wide Web-based tools (Google Earth and Microsoft Terraserver) were used to search high-resolution satellite imagery for patches of suitable habitat for globally and regionally rare tiger beetles on a 3,278 ha wildlife refuge in Maryland, USA. This tract is largely forested but contains scattered small open areas of sand and clay soils that are potential habitat for tiger beetles of conservation concern. Visual inspection of remotely sensed imagery resulted in the identification of 19 potential habitat patches, 15 of which yielded tiger beetle populations when surveyed on the ground. The number of species of tiger beetles recorded from this tract was increased from 3 to 8 and two new sites were discovered for the state sensitive species Cicindela scutellaris rugifrons Dejean. In addition, a small population of C. splendida Hentz was discovered, a species last reported from Maryland in 1948. The technique described here shows great promise for locating small patches of potential tiger beetle habitat in otherwise unsuitable landscapes.     

Status and conservation of an imperiled tiger beetle fauna in New York State,USA

New York has 22 documented species of tiger beetles (Coleoptera: Cicindelidae). Over half of these species are considered rare, at risk, or potentially extirpated from the state. These rare species specialize on three sandy habitat types under threat from human disturbance: beaches, pine barrens, and riparian cobble bars. In 2005, we began a status assessment of eight of New York’s rarest tiger beetles, examining museum records, searching the literature, and conducting over 130 field surveys of historical and new locations. Significant findings included (1) no detections of four of the eight taxa; (2) no vehicle-free beach habitat suitable for reintroducing Cicindela dorsalis dorsalis; (3) C. hirticollis at only 4 of 26 historical locations; (4) C. patruela patruela at only one site statewide; and (5) C. ancocisconensis at only 3 of 28 de novo survey sites. Additional species that might be declining deserve our attention, as do some threats to tiger beetle habitats, like lack of beach wilderness, fire suppression in pine barrens, and river damming. Rarity in tiger beetles is a result of varying ecologies, which suggest different conservation strategies. Future inventory and documentation of tiger beetle occurrences need to take into account the metapopulation structure and imperfect detectability of these rare insects.     

Tigers eating tigers: evidence of intraguild predation operating in an assemblage of tiger beetles

1. Co‐occurrence of closely related predators in a prey‐limited habitat appears to contradict the principle of competitive exclusion, however it may be explained through indirect effects, niche shifts, and intraguild predation. 2. The interactions between sympatric tiger beetle Cicindela species were examined. Cicindela circumpicta is the largest of three species (C. circumpicta, C. togata, C. fulgida) found in saline habitats throughout central North America. The temporal occurrence of these species overlaps, as does their spatial occurrence on exposed salt flats of saline marshes. During field observations, exoskeletal remains of C. togata were found at the study site in Nebraska, U.S.A. 3. In laboratory trials, male C. circumpicta ate C. togata in 38% of trials and female C. circumpicta ate C. togata in 50% of trials (n = 24). 4. In the field, potential prey, consisting mainly of small flies, was found mostly in shaded conditions but tiger beetles differed significantly in shade use, with C. circumpicta spending 70% of the time in the shade compared with ≈ 20% for C. togata. Differential habitat use was not explained by maximum temperature tolerances, which did not differ between the species. 5. Laboratory trials established that both tiger beetle species consumed small prey (apterous Drosophila) but C. togata was more efficient at capturing winged Drosophila. 6. Foraging efficiency, as measured by the time taken for a C. togata to capture three prey items, decreased significantly in the presence of other tiger beetles, especially C. circumpicta. 7. These results are an indication that intraguild predation and induced changes in foraging behaviour operate in the ecology of adult tiger beetles.     

Habitat segregation in four species of adult tiger beetles (Coleoptera: Cicindelidae)

ABSTRACT.

• 1 Habitat segregation in four species of tiger beetles, Cicindela cancellata Dejean, C.cardoni Fleutians, C.minuta Olivier and C.sumatrensis Herbst in a river bank ecosystem was studied in dry and wet seasons.
• 2 The four species segregated distinctly along the river beds into separate habitats, with occasional overlapping in both the seasons.
• 3 Among the habitat characteristics considered, vegetation, soil moisture and available prey-size were found to be important in species segregation.
• 4 D ²-analysis showed that the habitat preferences of C.cardoni and C.cancellata were closer to that of C.sumatrensis. The habitat of C.minuta was distinctly separated.
• 5 There was a positive correlation between the mandible length of each tiger beetle species and the length of prey captured.
• 6 Variance in mandible length within species was related to prey-length distribution pattern and to variance in habitats.

     

Glacial refuges and cryptic speciation in a Southern Palearctic tiger beetle (Coleoptera: Cicindelidae)

Pleistocene glaciations had a determining role for shaping the current distribution and diversity of organisms, especially in the Palearctic region. In this work, we carry out a phylogeographic analysis of Iberian and two Eastern European populations of the tiger beetle Calomera littoralis (Fabricius, 1787) in order to infer the processes that may have affected their evolutionary history. According to our results, the genetic diversity of central Iberian C. littoralis populations is very low. The haplotype networks also suggest that these populations experienced a genetic bottleneck in the past, possibly related to the last glacial maxima, similar to that observed in other cicindelid taxa. These results highlight the remarkable dispersal capacity of this species, being able to move freely from one locality to another, despite the relatively long distances of sub-optimal habitat that separates them. The genetic data of central Iberian populations contrast with those of the Eastern European populations, with higher genetic diversity and no hints of any past bottleneck. This can be explained by the different characteristics of both (Iberian and Pontic) glacial refuges. The high degree of genetic differentiation between the three C. littoralis clades, and the inclusion of C. lunulata between them, suggests that the three analysed populations could be considered as different cryptic species. In that case, C. littoralis may correspond to a species complex that is still undergoing a process of speciation, similar to that observed in Cicindela campestris.     

Diurnal Tiger Beetles (Coleoptera: Cicindelidae) Capture Prey Without Sight

Although much research has examined the process of prey capture by tiger beetles, an underlying assumption in this work is that tiger beetles are principally, or even exclusively, visual predators. Because this assumption is untested, we performed a series of experiments on four diurnally active tiger beetles in the Genus Cicindela. Individual beetles were placed in chambers in complete darkness and allowed to forage on apterous Drosophila for 6 h. Contrary to expectations, adults of all tested species captured more than 90% of prey items. These results show that other modalities can be used by tiger beetles during prey capture. Beyond potentially providing an explanation for observed night activity in tiger beetle species, the significance of these findings lies in the need to test underlying assumptions of even well-studied organisms.     

Stage‐dependent responses to emergent habitat heterogeneity: consequences for a predatory insect population in a coffee agroecosystem

Interactions among members of biological communities can create spatial patterns that effectively generate habitat heterogeneity for other members in the community, and this heterogeneity might be crucial for their persistence. For example, stage‐dependent vulnerability of a predatory lady beetle to aggression of the ant, Azteca instabilis, creates two habitat types that are utilized differently by the immature and adult life stages of the beetle. Due to a mutualistic association between A. instabilis and the hemipteran Coccus viridis – which is A. orbigera main prey in the area – only plants around ant nests have high C. viridis populations. Here, we report on a series of surveys at three different scales aimed at detecting how the presence and clustered distribution of ant nests affect the distribution of the different life stages of this predatory lady beetle in a coffee farm in Chiapas, Mexico. Both beetle adults and larvae were more abundant in areas with ant nests, but adults were restricted to the peripheries of highest ant activity and outside the reach of coffee bushes containing the highest densities of lady beetle larvae. The abundance of adult beetles located around trees with ants increased with the size of the ant nest clusters but the relationship is not significant for larvae. Thus, we suggest that A. orbigera undergoes an ontogenetic niche shift, not through shifting prey species, but through stage‐specific vulnerability differences against a competitor that renders areas of abundant prey populations inaccessible for adults but not for larvae. Together with evidence presented elsewhere, this study shows how an important predator is not only dependent on the existence of two qualitatively distinct habitat types, but also on the spatial distribution of these habitats. We suggest that this dependency arises due to the different responses that the predator's life stages have to this emergent spatial pattern.     

Anoxia tolerance of con-familial tiger beetle larvae is associated with differences in energy flow and anaerobiosis

In this study, we compared survivorship, heat dissipation and biochemical features of anaerobiosis of two tiger beetle species (Coleoptera: Cicindelidae) exposed to anoxia. One species commonly experiences environmental immersion from rainfall and snowmelt (Cicindela togata), and the habitat of the other (Amblycheila cylindriformis) is not prone to flooding. The ancestral genus, A. cylindriformis, survives anoxia for only 2 days at 25 °C. In response to anoxia, these larvae immediately lose locomotory abilities, tissue concentrations of ATP fall precipitously within 12 h, and significant amounts of lactate are quickly produced. In contrast, C. togata larvae tolerate anoxia for 5 days. Heat dissipation is downregulated to a greater degree than that seen in A. cylindriformis (3.4% versus 14% of standard normoxic rate, respectively), the ability for locomotion is maintained and normoxic levels of ATP are defended for at least 24 h. Lactate is not accumulated until well into anoxic bout, and significant amounts of alanine are also produced. This study provides evidence that tiger beetles differ in physiological responses to anoxia, and that these differences are correlated with flooding risk and with species distribution. Accepted: 1 March 2000     

Vocal divergence is concordant with genomic evidence for strong reproductive isolation in grasshopper mice (Onychomys)

Behavioral barriers to gene flow often evolve faster than intrinsic incompatibilities and can eliminate the opportunity for hybridization between interfertile species. While acoustic signal divergence is a common driver of premating isolation in birds and insects, its contribution to speciation in mammals is less studied. Here we characterize the incidence of, and potential barriers to, hybridization among three closely related species of grasshopper mice (genus Onychomys). All three species use long‐distance acoustic signals to attract and localize mates; Onychomys arenicola and Onychomys torridus are acoustically similar and morphologically cryptic whereas Onychomys leucogaster is larger and acoustically distinct. We used genotyping‐by‐sequencing (GBS) to test for evidence of introgression in 227 mice from allopatric and sympatric localities in the western United States and northern Mexico. We conducted laboratory mating trials for all species pairs to assess reproductive compatibility, and recorded vocalizations from O. arenicola and O. torridus in sympatry and allopatry to test for evidence of acoustic character displacement. Hybridization was rare in nature and, contrary to prior evidence for O. torridus/O. arenicola hybrids, only involved O. leucogaster and O. arenicola. In contrast, laboratory crosses between O. torridus and O. arenicola produced litters whereas O. leucogaster and O. arenicola crosses did not. Call fundamental frequency in O. torridus and O. arenicola was indistinguishable in allopatry but significantly differentiated in sympatry, a pattern consistent with reproductive character displacement. These results suggest that assortative mating based on a long‐distance signal is an important isolating mechanism between O. torridus and O. arenicola and highlight the importance of behavioral barriers in determining the permeability of species boundaries.     

Phylogeny of xanthopygine rove beetles (Coleoptera) based on six molecular loci

The rove beetle subtribe Xanthopygina (Coleoptera: Staphylinidae: Staphylininae: Staphylinini) is a species‐rich group of 27 neotropical genera that contains some of the largest and most brightly coloured of all staphylinid beetles. The monophyly of the subtribe has never been tested before, using a large dataset of taxa and genes. Bayesian and maximum likelihood analyses are used on individual genes (COI, 28S rDNA, wingless, arginine kinase, CAD and topoisomerase I) and the partitioned concatenated dataset to test for monophyly and examine the relationships among Xanthopygina genera. Xanthopygina (excluding Philothalpus) are shown to be a monophyletic group with strong support values. The genus Philothalpus is removed from Xanthopygina and placed in the tribe Staphylinini as incertae sedis. Four distinct clades of Xanthopygina genera are recognized. The origin of Xanthopygina is hypothesized to be in the Late Cretaceous or later and the origin of myrmecophilous adaptations is discussed.     

Evidence of temperature‐independent metabolic rates in diurnal Namib Desert tenebrionid beetles

To investigate whether the sensitivity to environmental temperature varies between nocturnal and diurnal species of tenebrionid beetle, the metabolic rates of three diurnal species (Onymacris plana Peringuey, Onymacris rugatipennis Haag and Physadesmia globosa Haag) and three nocturnal species (Epiphysa arenicola Penrith, Gonopus sp. and Stips sp.) of beetles from the Namib Desert are measured over a range of temperatures (15–40 °C) that are experienced by these beetles in their natural habitat. The diurnal species O. plana, O. rugatipennis and P. globosa exhibit temperature‐independent metabolic rates (mean Q₁₀ = 1.2) within temperature ranges that are ecologically relevant for diurnal desert beetles (30–40 °C). Onymacris plana, in particular, has a 20–40 °C rate–temperature slope (0.007 log₁₀ mL O₂ h^?1 g^?1 °C^?1; Q₁₀ = 1.1) that is less than half that of the other five beetle species (0.022–0.063 log₁₀ mL O₂ h^?1 g^?1 °C^?1; Q₁₀ ranges from 1.3–1.9), suggesting that O. plana is more metabolically independent of temperature than the other nocturnal and diurnal tenebrionids being investigated. Animals with metabolic rates that are decoupled from body temperature (or ambient temperature) may have an ecological advantage that allows them to exploit thermal and spatial niches during extreme temperature conditions.     

Host and environmental influences on the gut bacterial community of carabid beetles in distinct paddy fields

The relationship between the gut bacterial communities of carabid beetles and their habitats holds implications for understanding ecological dynamics. This study examined the gut bacterial communities of two carabid beetle species, Chlaenius pallipes and Pheropsophus jessoensis, in terraced and flat paddy fields. Differences in gut bacterial communities were evident at the species level and were based on habitat. Specifically, P. jessoensis had a greater presence of Firmicutes and Proteobacteria in terraced fields but more Actinobacteria in flatland fields. In comparison, C. pallipes consistently showed high levels of Firmicutes in both habitats. These differences were reflected at class and genus levels, emphasizing the role of host specificity in shaping gut microbiota. Alpha diversity metrics indicated that P. jessoensis hosted a more diverse bacterial community than C. pallipes. Terraced fields, however, showed slightly reduced diversity in P. jessoensis, suggesting environmental effects on microbial populations. Beta diversity analysis using Bray–Curtis distances differentiated the bacterial communities of the two beetles. Multivariate analysis of variance reinforced these findings. Insights from the Sloan neutral model indicate that environmental factors predominantly influence bacterial community assembly through stochastic processes. Functionally, metabolism was highlighted, indicating the role of gut bacteria in beetle metabolic processes. Notably, energy metabolism varied between field types, revealing environmental effects on gut bacterial functions. This study offers in-depth insights into interactions between host-specific and environmental factors influencing gut bacterial communities of carabid beetles, contributing to a broader understanding of microbial ecology and the roles of environment and host in microbiota dynamics.     

Phylogeny of haplo–diploid,fungus‐growing ambrosia beetles (Curculionidae: Scolytinae: Xyleborini) inferred from molecular and morphological data

Cognato, A. I., Hulcr, J., Dole, S. A. & Jordal, B. H. (2010). Phylogeny of haplo‐diploid, fungus‐growing ambrosia beetles (Curculionidae: Scolytinae: Xyleborini) inferred from molecular and morphological data. —Zoologica Scripta, 40, 174–186. The ambrosia beetle tribe Xyleborini currently contains 30 genera and approximately 1200 species which are distributed throughout worldwide forests with most diversity located in the tropics. They also represent the most invasive scolytines in North America. Despite economic concerns and biological curiosity with this group, a comprehensive understanding of generic boundaries and the evolutionary relationship among species is lacking. In this study, we include 155 xyleborine species representing 23 genera in parsimony and Bayesian analyses using 3925 nucleotides from mitochondrial (COI) and nuclear genomes (28S, ArgK, CAD, EF‐1α) and 39 morphological characters. The phylogenies resulting from the parsimony analyses, which treated gap positions either as missing or fifth character states, and the Bayesian analysis were generally similar. Clades with high support or posterior probabilities were found in all trees, while those with low support were not recovered by all analyses. Fourteen of the 23 genera were monophyletic although not all relationships among the genera were resolved. We show monophyly of several species groups associated with particular morphological and biological characters and suggest recognition of these groups as genera. Most interesting was the monophyly of South and Central American species representing several genera. This finding suggests recent and fast radiation of xyleborines in the New World accompanied by morphological and biological diversification.     

Recent rapid speciation and ecomorph divergence in Indo‐Australian sea snakes

The viviparous sea snakes (Hydrophiinae) are a young radiation of at least 62 species that display spectacular morphological diversity and high levels of local sympatry. To shed light on the mechanisms underlying sea snake diversification, we investigated recent speciation and eco‐morphological differentiation in a clade of four nominal species with overlapping ranges in Southeast Asia and Australia. Analyses of morphology and stomach contents identified the presence of two distinct ecomorphs: a ‘macrocephalic’ ecomorph that reaches >2 m in length, has a large head and feeds on crevice‐dwelling eels and gobies; and a ‘microcephalic’ ecomorph that rarely exceeds 1 m in length, has a small head and narrow fore‐body and hunts snake eels in burrows. Mitochondrial sequences show a lack of reciprocal monophyly between ecomorphs and among putative species. However, individual assignment based on newly developed microsatellites separated co‐distributed specimens into four significantly differentiated clusters corresponding to morphological species designations, indicating limited recent gene flow and progress towards speciation. A coalescent species tree (based on mitochondrial and nuclear sequences) and isolation‐migration model (mitochondrial and microsatellite markers) suggest between one and three transitions between ecomorphs within the last approximately 1.2 million to approximately 840 000 years. In particular, the macrocephalic ‘eastern’ population of Hydrophis cyanocinctus and microcephalic H. melanocephalus appear to have diverged very recently and rapidly, resulting in major phenotypic differences and restriction of gene flow in sympatry. These results highlight the viviparous sea snakes as a promising system for speciation studies in the marine environment.     

Grouse moor management: habitat and conservation implications for invertebrates in southern Scotland

The distribution of ground beetle, rove beetle, spider and plant bug species assemblages, and the occurrence of other beetle species, was investigated in a five-year survey of a grouse moor in the Scottish borders, some of which was managed by burning, cutting and herbicide application. Multivariate analyses were used to assess the relationship between assemblage distribution and a number of environmental variables. The management of dry Calluna moor had a positive effect on the habitat diversity for ground beetles and plant bugs but had little effect on rove beetles and spiders. A total of 39 nationally rare and scarce species (38 beetle, 1 plant bug) was recorded in the survey. The most important habitat present was on streamside sites, especially sediment. A number of these rarer species were restricted to sites managed by burning and cutting but other species were only found on unmanaged wet Calluna moor. Molinia-dominated moor was generally of poorer quality than Calluna sites, with fewer rare and scarce species and lower site rarity values based on the ground beetle species recorded. The highest median site rarity scores were for dry, open, managed Calluna sites. In order to maximise both habitat diversity and the incidence of rare and scarce species on grouse moor, a mosaic of both managed and undisturbed patches differing in soil characteristics, plant composition and vegetation structure appears to be required.     

The Maghreb – one more important biodiversity hot spot for tiger beetle fauna (Coleoptera,Carabidae, Cicindelinae) in the Mediterranean region

The tiger beetle fauna of the Maghreb region is one of the richest in the Palaearctic, including 22 species and 5 subspecies and 19% of all Palaearctic species of Cicindelinae. Assembled to their chorotypes, the Maghreb tiger beetles fall into eight different groups that include Maghreb endemics (26% of fauna), Mediterranean (7%), West Mediterranean (40%), North African (4%), Mediterranean-Westturanian (4%), West Palaearctic (4%), Afrotropico-Indo-Mediterranean (4%), and Saharian (11%) species. The Mediterranean Sclerophyl and Atlas Steppe are the Maghreb biogeographical provinces with the highest species richness, while the Sahara Desert has the lowest Cicindelinae diversity. Twenty-five cicindelid species and subspecies (93% of Maghreb fauna) are restricted to only one or two habitat types in lowland areas. Only Calomera littoralis littoralis and Lophyra flexuosa flexuosa are recognized as eurytopic species and occur in three types of habitat. The highest tiger beetle diversity characterizes salt marshes and river banks (in both cases 11 species and subspecies or 41% of Maghreb fauna). Approximately 85% of all Maghreb tiger beetle species and subspecies are found in habitats potentially endangered by human activity.     

Phoretic Poecilochirus mites specialize on their burying beetle hosts

Recurring species interactions can cause species to adapt to each other. Specialization will increase the fitness of symbionts in the coevolved association but may reduce the flexibility of symbiont choice as it will often decrease fitness in interactions with other than the main symbiont species. We analyzed the fitness interactions between a complex of two cryptic mite species and their sympatric burying beetle hosts in a European population. Poecilochirus mites (Mesostigmata, Parasitidae) are phoretic on burying beetles and reproduce alongside beetles, while these care for their offspring at vertebrate carcasses. While Poecilochirus carabi is typically found on Nicrophorus vespilloides beetles, P. necrophori is associated with N. vespillo. It has long been known that the mites discriminate between the two beetle species, but the fitness consequences of this choice remained unknown. We experimentally associated both mite species with both beetle species and found that mite fitness suffered when mites reproduced alongside a nonpreferred host. In turn, there is evidence that one of the beetle species is better able to cope with the mite species they are typically associated with. The overall fitness effect of mites on beetles was negative in our laboratory experiments. The Poecilochirus mites studied here are thus specialized competitors or parasites of burying beetles.     

Carrion beetles succession in three different habitats in Riyadh,Saudi Arabia

A main objective of the study is the establishment of a forensic entomological database for Riyadh, Saudi Arabia. Decomposition processes and beetle succession were analysed on rabbit carcasses in three different habitats (agricultural, desert and urban) in the period from May to July 2014. Due to the effects of the high temperature at the study sites, carrion reached the dry stage within 12 days in the agricultural habitat, and 6 days in the desert and urban habitats. A total of 125 beetles belonging to eight species and five families were collected during the decaying process, with their abundances increasing from the fresh to decay stages. The prevailing species belonged to the families of Dermestidae and Histeridae. It was not possible to confirm any definitive relationship between the occurrence of a single species and a particular stage of decomposition. The beetle communities were also not distinctively different between desert and urban habitats, but a distinct community was evident in the agriculture habitat. In addition, there were distinct beetle communities between the decay stage and the other stages. The dry stage recorded the lowest number of beetles. This study indicated that, the habitat type had an effect on the decay process and the abundance rate of the beetles.     

Morphological variability in Lophyra flexuosa (Fabricius, 1787) (Coleoptera,Cicindelidae) in desert countries is affected by sexual dimorphism and geographic aspect

Lophyra flexuosa, a eurytopic tiger beetle characterized by long phenological activity, wide geographic and altitudinal distribution, and occurring in the highest number of habitats among all Cicindelidae known from North Africa, was chosen to study its geographic variation in morphology and sexual dimorphism. Here, we found significant sexual dimorphism exhibited in larger body size of females and longer mandibles in males, which can be explained by different roles of particular sexes in courtship. Moreover, we recorded significant differences in body sizes between western and eastern Maghreb populations which could suggest genetic isolation between these populations. As the species is related to habitats placed close to the water reservoirs, which in the desert countries are under significant human pressure (including climate change), we expect a reduction of habitat occupied by this taxon. Therefore, the geographic morphological variability that we observe today in the tiger beetle Lophyra flexuosa in the future could lead to speciation.